Blockage maybe?

[Bental]

Gday lads. Alex from Aus here.

Looking at an ac here, split ducted, tripping head pressure immediately upon start.
History wise, I've come in at the end. Previously the compressor has burnt out and been replaced, the sparkies doing it made a few errors though. Each time fixed they have reclaimed old gas and reused, after burn out a regular L/L drier was installed in pipe run on suction (cooling) due to space restrictions inside unit.
Wiring is a mess too, I don't know what else has been done. Apparently before diagnosing as Reversing Valve, the guy thought it was over charged and removed gas. Then added it back. Then the pressure shot up.

Now this is where i come in. I replaced the valve and tested it by energizing and de-energizing the coil, and hearing the vessel click over. But still same problem.
Initally the unit ran, but got very hot and iced on the liquid line.This was in about 5 minutes. Since then it has tripped hp immediatly, within a second of resetting it.
I'm thinking the muffler could be blocked, the discharge out of the compressor gets hot and stops at the muffler after a few resets.
I also replaced the L/L drier with a bidirectional burnout drier.

I charged and pressure tested with nitrogen and pulled a good vacuum but reused old gas under direction (didn't like it)

Any help will be appreciated. Cheers guys.

[tradybrad]

Hey Alex what brand machine are you working on? Really need to know refrigerant type, metering device type, what was your suction pressure & superheat when unit was operating. Any extra info you can give would be great. Brad.

[Bental]

It's an Airwell, not too sure on the model number as the sticker is gone.
R22 gas. Pressure wise I don't fully recall. However R22 temp scale, was at 25'C discharge pressure and -5'C suction. Ambient air on was probably around 20'C. I was always taught easiest way to charge a unit that was working correctly to about 15-20'C above ambient on the discharge line and never had a problem.
So I figured it would be short of gas. Suction line was warm too and compressor was getting hot quite quickly.
Capillary metering device.
Superheat I do not know.

Has anyone ever heard of a muffler getting blocked though? I wouldn't have thought it to be very poissible, even if the system wasn't treated correctly after a burn out.

[The Viking]

The compressor has been replaced by sparkies...?

How likely is it that they both used OFN to protect the system from soot and knew how to do a good braze?

See where the icing starts, that's where your blockage is likely to be.

Personally, I would probably just quietly walk away and tell the customer to buy a new, modern, system.

:cool:

[Bental]

Installed a bunch of access ports now.
After this vac we shall see.
Its either the muffler or the condensor... If you catch my drift lol.